A corpora



Nov. 6, 1928. 7 1,691,011

E. W. JACKSON BEACON Filed Jan. 2 1926 Patented Nov. (i, 192 8.

UNITED sTATas PATENroFFmE.

EDWARD W. JACKSON, OF PHILADELPHIA, PENNSYLVANIA, ASSiIIGNOR TO B. B. T. CORPORATION OF AMERICA, OF PHILADELPHIA, PENNSYLVANIA, A CORPORA- TION or DELAWARE.

' BEACON.

Application filed. January 29, 1926 serial in). 84.540,

Objects of the present invention are to definitely mark direction or a course or courses; to locate the marked directlon or course or courses; to provide simple, reliable and eflicient mechanism for operating a beacon light in such a way that either or both of the foregoing objects can be accomplished; and to provide for individualizing a beacon light to distinguish it from other beacon lights.

Other objects of the invention will appear from the following description at the end of which the invention will be claimed.

The following description will be made n connection with the embodiment of the invention chosen from among other embodimerits for the sake of illustration in the accompanying drawing in which Figure 1 is a diagrammatic View, partly in section, illustrating features of the invention.

Fig. 2 is a. diagrammatic plan view of some of the parts shown in Fig. 2, and 1 Fig. 3 is a diagrammatic view hereinafter 2 referred to. V

In the drawing 1 is a search-light mounted to revolve about the axis 2. 3 is a crank arm shown as revolved by a motor 4 through reduction gearing 5. 6 is a rack mounted for 80 reciprocation, and it is connected with the 7 connecting rod 7 of the crank. 8 is a pinion meshing with the rack and it is connected with the Searchlight 1 through the interven-' tion of gearing 9. As shown the wrist pin I 85 10 is adjustable on the crank arm, and the connecting rod 7 is connected with a block-11 slidably connected with the rack and centered by springs 12. .13 are adjustable stops for limiting the range of reciprocation of the rack. I

The mode of operation may be described in connection with air planes, but the invention is applicable to other uses and purposes on both land and sea. I,

Rotation of the-crank causes reciprocation of the rack with a motion that may be called" harmonic motion and in which there is a dwell at each end of the stroke of the rack and an acceleration at the middlepart of each m stroke. Referring to Fig. 3, each of the lines k or arrows 14 and 15 represent an airplane course. The gearing between the rack and search light is such that the beam of the search-light coincides with the course 14 at one end of the stroke of the rack and with the course 15 at the other endof the stroke of the rack, so that there is a dwell in the movement ofthe beam when it coincides with or lies in the 'course. In an airplane approaching the beacon thebeam is only made visible when directlyhead on, so that if a dwell in the motion of the beam is observed it is known that the airplane is on its course. cannot be discerned in the movement of the beam, i't is known that the airplaneis ofi its which, for example, has traversed the course 14 and is traversing the course 15. However, on the latter course the aviator-must If a'dwell the course 14 or 15, and also to an airplane I look backward. I As far as has been described,

the course has been definitely marked but if an airplane is off the course,'to one side or the other of it, it is possibleby the present invention to indicate onwhich side of the course the airplane is located. For this purpose the beam of li ht is made to travel more' than other, at each successive stroke ofthe rack 360,'first 1n one direction. and then in the an airplane travelling a false course indicated by the dotted line 16, will not observe the dwell in the movement of the beam which takes place inthecorrect course 14, but will observe two succeeding flashes of the beam from which it is known that it is on the si e ofthe course 14 upon which the'line 16 lies. If an airplane is following the false or erroneous course 17 the dwell in the movement of the beam that occurs only on the true course 14. will not be seen, but a comparatively quick single flash of the beam will be seen and will indicate that the aviator is ofi' the course 14 to'the side upon which the line 17 lies. The flash seen on the false course 17 is short "because rotation of the light is comparatively fast sincev it is due to the movement .ofthe rack at an intermediate portion-of its travel.

To individualizea beacon, the dwell in the movement of the beam on the true course may be lengthened by adjustments of the stops 13 which hold the rack whilst the crank completes a part of its revolution, the sprin s V yielding for that purpose. The part of t e revolution traversed by the crank under these circumstances is the part of the revolution nearest to the axis or line of the rack or the part Where the crank and connecting rod more nearly occupy straight line position. By adjusting the wrist pin the extent to which the light is turned for each reciprocation of the rack and first in one direction and then in the other can be adjusted to suit various courses. In the case of a double ended search light the true course can be indicated as is obvious in the manner above described.

It will be obvious to those skilled in the art to which the invention relates that modifications may be made in details of construction and arrangement and in matters of mere form without departing from the spirit of the invention which is not limited to such matters or otherwise than as the prior art and the appended claim may require.

I claim:

A beacon comprising a revoluble searchlight of which the beam is constantly swept over the entire field of approach, a rack and pinion mechanism for oscillating it, a crank mechanism for reciprocating the rack, a normally centered element connected with and movable in respect to the rack and to which the connecting rod of the crank mechanism is connected, and stop means for augmenting the dwell in the motion of the rack near the ends of the strokes.

EDWARD W. JACKSON. 

